Britney on Justin?

Young love ... there's nothing like it. And when it goes wrong, young hearts turn bitter. First Justin whined about Britney in Cry Me A River, now, it appears, Britney strikes back in the sure to get attention move (Mommy Madonna taught her well about PR), called Toxic.

Does she really want to poison her cheating ex? And if she were to procure such a potion, wouldn't she -- no stranger to upchucking -- have mercy on him?